ral thrush is a yeast infection inside the mouth. It is most common in infants, children, and older people. It is usually a mild infection that normally resolves in about fourteen days. The infection can become more severe when a person has a compromised immune system. In these cases, the infection can spread and lead to more serious problems.

Oral Thrush Symptoms

Oral thrush or candidiasis may not show any signs or symptoms initially, or the infection may develop suddenly with various signs and symptoms, including:

  • Lesions in the mouth that appear as creamy white and slightly raised patches. These generally form on the tongue and inside of the cheeks. They can also develop on the roof of the mouth, throat, gums, lips, tonsils, and the esophagus in severe cases.
  • Redness and soreness in the mouth.
  • Cracking, itchiness, or redness at the corners of the mouth.
  • A cottony feeling in the mouth.
  • Less sense of taste.
  • Difficulty swallowing if the infection affects the esophagus.
  • Bleeding with irritation of patchy areas.
  • Difficulty eating.

Causes of Oral Thrush

Candida fungus causes the common condition known as oral thrush. The most common candida fungus which occurs naturally in the mouth is albicans. Ordinarily, it is present in a small amount and causes no problems. However, with a compromised immune system, there can be an overgrowth of the fungus and the development of oral thrush symptoms.

Oral thrush

Risk Factors

You are at a higher risk of an oral thrush infection under certain circumstances, such as:

  • Taking some medicines such as steroids or antibiotics. Medications that lower the amount of friendly microorganisms in your body can cause an overgrowth of Candida albicans fungus.
  • Some cancer treatments. Some chemotherapy medications and radiation treatments can harm healthy cells. When this cell damage happens, you are more susceptible to an oral thrush infection.
  • Illnesses that weaken the immune system. Diseases such as leukemia and HIV increase the risk of an oral fungal infection.
  • Wearing dentures. Upper dentures, especially, are prone to cause an oral thrush infection.
  • Dry mouth. Illnesses or medications that cause dry mouth which is a risk factor for candida infection.
  • Uncontrolled diabetes causes more salivary sugar, which promotes the proliferation of candida.
  • Hormone changes that occur during pregnancy can cause oral thrush.
  • Smoking.


Thrush has such a distinctive appearance that your dentist or health care provider can typically diagnose the infection by looking in your mouth. In severe cases involving the esophagus, additional tests may be needed such as a throat culture, endoscopy, or radiographs of the esophagus.


Oral thrush is normally treated with antifungal medications applied inside the mouth for seven to fourteen days. These medications are prescribed in tablets, liquids, or lozenge:

  • Clotrimazole
  • Nystatin
  • Miconazole
  • Sporanox
  • Amphotericin
  • Fluconazole

In addition to antifungal medications, these self-care recommendations help alleviate symptoms and resolve the infection:

  • Consistent oral hygiene. Brush and floss regularly. Replace your toothbrush more frequently, and do not share your toothbrush.
  • Rinse your mouth with warm salt water. Use one-half teaspoon of salt and a glass of warm water.
  • Lightly scrape the patchy lesions with a soft toothbrush.
  • Avoid mouthwashes and mouth sprays.
  • Eat unsweetened yogurt to replenish healthy bacteria.
  • Keep dentures cleaned and disinfected. Ask your dentist for recommendations on how to best accomplish this with your denture.


Maintaining good overall health helps prevent oral thrush. Measures you can take include:

  • If you require a corticosteroid inhaler, rinse your mouth with water or brush your teeth after its use.
  • Maintain optimal oral hygiene with twice daily toothbrushing, daily flossing, and regular checkups with your dentist.
  • Eat a healthy, low-sugar diet.
  • If you have diabetes, maintain good blood sugar levels.
  • Treat vaginal yeast infections without delay.
  • If you have a condition or take a medication that causes dry mouth, ask your dentist or physician how to treat it.
  • Treat chronic illnesses as prescribed by your physician.
  • Don’t overuse antibacterial mouthwashes.
  • Quit smoking.
quit smoking

Frequently Asked Questions

– Is oral thrush contagious?

It is not contagious in the same manner as other infections. Still, oral thrush may develop in someone already at an elevated risk for acquiring it due to a weakened immune system. The fungal infection can also transmit from an infant to the mother during breastfeeding. The incubation period for oral candida infections is between two and five days.

– How long does oral thrush last without treatment?

If you choose not to treat oral thrush, it will usually resolve in three to eight weeks. Very mild cases can heal in less time without any medications. More severe cases can clear up in about two weeks with antifungal medications.

– Why do I keep getting oral thrush?

Although oral thrush is not usually a major medical problem itself, it can indicate a more serious medical condition. Many illnesses such as diabetes, leukemia, and cancer cause suppression of the immune system, which is a significant risk factor for oral thrush.

— By Dr. Steven Received his Doctor of Dental Medicine (DMD) from the Medical College of Georgia before practicing general dentistry in the United States Navy. He then completed a residency in endodontics at the Medical College of Georgia.

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